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W. H. OSBORNE & G. R. MEITZLER.

ELECTRIC SOLDERING IRON.

Patented May '7, 1895.

: NORRVS Fan s co. were UNITED STATES PATENT OFFICE.

IVILLIAM H. OSBORNE, OF PRINCES BAY, NEIV YORK, AND GEORGE R. MEITZLER,OF CINCINNATI, OHIO.

ELECTRIC SOLDERlNG-IRON.

SPECIFICATION forming part of Letters Patent No. 538,695, dated May 7,1895.

Application filed February 13, 1895. Serial No. 588,237. (No model.)

To all whom it may concern:

Be it known that we, WILLIAM H. OSBORNE, residing at Princes Bay,Richmond county, State of New York, and GEORGE R. MEITZLER, residing atCincinnati, Hamilton county, State of Ohio, citizens of the UnitedStates, have invented certain new and useful Improvements in ElectricSoldering-Irons; and we do declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same,attention being called to the accompanying drawings, with thereference-numerals marked thereon, which form a part of thisspecification.

This invention relates to improvements in electrically heated solderingirons of the kind where the heat generated by the electric current,while passing through a resistance coil, is utilized to heat theimplement. The different features relate to a specially constructedheating-core wherein the wire of the resistance coil is insulated andwhich receives the heat generated by the latter for transmission byradiation to the tool; to a construction which aids this transmission,to a construction which gives ready access to the heating core, topermit its replacing and convenient re-connection to the electriccircuit and finally they relate to an attachment for supplying solderwhich is operated electrically for the purpose of advancing the latterto the point of the tool where it is used.

In the following specification and particularly pointed out in theclaims at the end thereof is found a full description of our invention,its operation, parts and construction, which latter is also illustratedin the accompanying drawings, in which Figure 1 is a longitudinalsection of an electric soldering-iron provided with our improvements.Fig. 2 is a horizontal cross-section on line 2 2 of Fig. 1. Figs. 3 and4 are similar views taken on line 3 a of Fig. 1 and showing the oppositesurfaces of said section, Fig. 8 showing the upper and Fig. 4. the lowersurface. Fig. 5 is a side elevation, partly in longitudinal section,showing the electrically-operated solder-supplying attachment inposition.

8, is the pointed head of the tool of customary shape but preferablycylindrical and hollow. Its inner end is screw threaded and connects toa correspondingly threaded socket shank 10.

11, is a lock-nut on the latter and screwing against socket 9, preventsthe same from turning on the shank. At its other end this latter hasaffixed to it the hollow handle 12, through the open rear end of whichthe current carrying wires 13 and let, enter. These wires are properlywound and covered with insulating material and of great pliability, soas not to interfere with the manipulation of the tool. This rear-end ofthe handle consists of a removable cap 15, which permits access to theinterior of the handle for the purpose of affixing a nut 16, to theinner end of shank 10, to hold the handle thereon, the front end of thelatter being held by a shoulder 17 rigidly aflixed to the shank. Thisremovable cap also permits the wire to be knotted as shown at 18, whichknot is of a size to prevent it from slipping through the opening in thecap and whereby any strain or pull on the wire is kept from transmissionto its interior parts, thereby preventing injury and separation to theinterior connections of the wire.

Across the open end of shank 10, and against the bottom of socket 9,rests a disk 19, of insulating material, as hard rubber for instance, inwhich are embedded a ring 21, and a plug 22, both of metal and formingelectrical conductors. The naked ends of wires 13 and 1a are passedthrough this disk and. connect one to ring 21,the other to plug 22.23,is another similar disk also of insulating material and has affixedto it two metallic tongues 2-4, and 25, so located thereon that whenthis latter disk is brought opposite to the other disk, and sufficientlyclose to it these metallic tongues will come in full contact, the onewith ring 21, the other with plug 22. On the other side of disk 23, isthe heating core 26, consisting substantially of several concentriccoils of fine wire of high electrical resistance, all formed however ofone continuous piece of Wire, the ends of which pierce disk 23, andconnect, one to each of the tongues 24 and 25. As is well understood,the purpose of this fine wire core is to produce, by its resistance tothe free passage of the electric current, the heat which is required toheat the soldering iron. The difficulty encountered heretofore inconstructing this part in a practical manner for sucdesired for anypurpose. taken out and a new one inserted after the cessful operationhas been to find a material which would sufficiently insulate to preventshort circuits, the volutes of the coils and the coils themselves fromeach other, and at the same time form a heat-conductor exactly properfor the purpose. It should take up the heat with sufiicient readiness,but at the same time retard it in a manner to hold it within the coreand prevent its too free radiation. powdered calcined soap-stone with asmall percentage of lamp-black, held together by a suitable binder,preferably oil and water-glass. If necessary water is added to give it aproper consistency for working. In its plastic state a layer is putaround a mandrel and after drying, the formation of the wire core isbegun by starting from one end with the winding of the first or innerwire coil. Another layer of the plastic mass is applied over this firstcoil and after drying the second coil is wound, starting from the endwhere the first coil was finished and winding back toward the other end.In this manner a suflicient number of coils are added, until therequired resistance is obtained, by winding first from one end and thenback again to the other, with a layer of the aforesaid mass between eachcoil and a final outer layer on the outer coil.

The winding is finished in a manner to bring the two wire-ends to thesame end of the core, to admit their connection to tongues 24 and 25,for which purpose these ends pierce disk 23. This is all done after thewhole is suficientl y dry and has been withdrawn from the mandrel onwhich it was formed. The so completed core is now inserted within thehollow head 8, into which it freely fits, disk 23, slightly overlappingthe inner edge thereof. The head is then screwed into socket 9, untildisk 23, rests against a shoulder in the latter, against which it isheld in position by the edge of the soldering head. At the same timetongues 24 and 25 have come in contact with ring 21 and plug 22respectively, so that a complete circuit is now formed, the currentpassing in on wire 13, to ring 21, to tongue 24, to and through theresistance coils forming part of the heating core 26, out of the latterto tongue 25, to plug 22 and out on wire 14.

The wire forming part of heating core 26, being finer and of higherelectrical resistance than the balance of the current-conductors,becomes hot and heats the material which forms the other part of thecore which then transmits the heat to the soldering head. To utilize thehead of the core as fully as possible 2. copper or iron core 27, isprovided within the hollow space of core 26, which also becomes heatedand by being connected to the interior of the soldering point, aids theheating of the same by transmitting its heat to it.

The separable connection of the electric con- I ductors between disks 19and 23, becomes of advantage when the replacing of core 26, is It may bereadily soldering head is unscrewed. The re-establishment of theconnection between the elec trical conductors presents no difficulties,because tongues 24 and 25, find always their proper positions on ring 21and plug 22 themselves.

When desired, an attachment to supply solder may be added, whichconsists of a case 30, connected to or forming part of shank 10.

This material consists preferably .oLjMithin it is loosely pivoted adisk 31, and a hollow snout 32 leads from its interior close to thesoldering point. This snout is midways supported by abrace 33. Thesolder is in form of a flat strip 34, which is wound around a post 35,mounted on disk 31, and provided with a split to receive the inner endof the solder-strip, to prevent it from slipping thereon and cause it torotate with the disk and unwind therefrom. The edge of the latter isprovided with ratchet-teeth with which engages the hooked end of a rod36, which extends back to within the handle where it is guided bycross-pieces 37, 37. The other end of this rod carries an armature 38,which is opposite the end of a magnet 39, from which it is held normallyseparated by a spring 41, acting against a collar on rod 36. When theoperation ot tliis attachment is desired, a spring-actuated switch 42 isdepressed by the palm of the hand which holds the tool, said switchthen-diverting the current through the magnetwfliifih now attracts thearmature opposite it and draws rod 36, toward it. This causes the hookedend of the latter to rotate disk 31, and tlresolder to unwind therefrom,which latter now moves out of snout 32 and against the point of thetool. When the switch is released,th'e"magnet is cut out of the circuitagain and releases the armature, which with rod 36 is carriedjorward byspring 41, the hooked end of the rod passing passively over the teeth cmthe disk and stopping in position for 'tllfnext operation. the magnet isthus within the electric circuit of the tool, the current passes throughits coil While and through short wires 43 and 44, connecting Y with oneof the main-wires. As to wire 44, this connection is permanent while asto wire 43, it is only temporary and completed by the movable arm ofswitch 42 over which the current passes from wire 13 to wire 43 andthrough the coil of the magnet. In its other position, the switch simplycompletes conductor 13, and cuts wire 43 out of the circuit.

One of the sides of case 30, should be remov heated soldering irons arepreferable on account of the greater cleanliness attending theirheating.

Having described our invention, we claim as new 1. In an electricallyheated soldering iron, adapted to receive current-carrying conductorsand having a hollow soldering head, the combination of a heating coreinclosed within the latter, consisting substantially of layers of wireof high resistance, forming part of the current carrying circuitsupported and inclosed by a heat-absorbing and conveying mass consistingsubstantially of calcined powdered soap-stone with a small percentage oflamp-black held together by a suitable binder in which mass theresistance wire is embedded while in its plastic state said mass alsosupporting the individual layers or bights of the wire in position withreference to the adjoining ones and insulating them from each other.

2. In an electrically heated soldering iron adapted to receivecurrent-carrying conductors and having a hollow soldering head, thecombination of an iron heat-transmitting core 27 afiixed centrallywithin the interior of the head, back of the point and with its otherfree end ext-ending inwardly a hollow heating core 26, consistingsubstantially of insulated layers of wire of high resistance which forma part of the current-carrying circuit, said heating core occupying theinterior of the hollow soldering head and surrounding loosely the ironcore 27, with an air space between them.

3. In an electrically heated soldering iron, the combination of aremovable hollow soldering head, a heating core for it consistingsubstantially of insulated layers of wire of high resistance, formed outof one continuous piece, the ends of which protrude at the open end ofthe soldering head where they are provided with contact pieces,a hollowshank 10, adapted to receive the soldering head and carrying currentconveying wires, the ends of which protrude at the open end of the shankwhere they are also provided with contact pieces, all of which latterare so placed with reference to each other, that when the head isconnected to the shank, these contact pieces meet and establish acomplete elect-rical circuit.

4. In an electrically heated soldering iron, the combination of a shank10,adapted'to re ceive a soldering head and carrying wires formingelectrical conductors, the ends of which protrude out of the hollowshank, a disk 19, of insulating material thereat through which theseprotruding wire-ends pass, a ring 21, and a central plug 22, bothforming conduo-tors, embedded in disk 19, and to each of which one ofthe wire-ends connects, a hollow soldering head adapted to be connectedto shank 10, a heating-core within it, consisting substantially ofinsulated wire of high resistance, a disk 23, of insulating materialwhich receives the ends of the resistance wire which pass therethrough,tongues 2t, 25 forming conductors to which said ends connect, saidtongues secured to disk 23 in a position that when this latter isbrought opposite disk 19, during the connection of the head to theshank, one of them will come in contact with ring 21, while the othertongue comes in contact with plug 22, whereby the electrical circuitthrough the tool is completed.

5. In an electrically heated soldering iron, the combination of a hollowsoldering head, a heating core therein consisting substantially ofinsulated wire of high resistance, the ends of which terminate at theopen end of the soldering head where they are provided with contactpieces, a hollow shank 10, provided with a screw-threaded socket 9,which is adapted to receive the soldering head, current carryingconductors passing through the hollow shank, their ends terminating insocket 9, where they are provided with contactpieces, all of theselatter so placed, that when the soldering head is screwed into socket 9,they complete the electrical circuit.

6. In an electrically heated soldering iron, the combination of asoldering head, provided with a heating core, a hollow shank with ahollow handle thereon, a removable perforated cap 15, on the end of thelatter, current carrying wires passing through shark and handle, knottedat 18, within the latter, such knot being larger than the perforationthrough cap 15, to prevent exterior strains on the wires from beingtransmitted to their interior connections.

'7. In an electrically heated soldering iron, the combination of asoldering head, a heating core for it, a hollow shank carrying electricconductors and provided with a shoulder 17, a hollow handle on theshank, a nut16 on the latter and within the hollow part of the ban dlewhereby this latter in conjunction with shoulder 17 is held and confinedin position on the shank.

8. In combination with an electrically heated soldering iron, having asoldering head with a heating core for it and a hollow shank and handle,asolder-supplying attachment adapted to carrya rolled strip of solder, asnout 32, for guiding the latter to the point where it is used, afeed-mechanism for moving the solder, a hooked rod 36, provided with anarmature and supported in guides in a manner to confine it toalongitudinal movement, a magnet opposite the armature, a spring forholding them normally separated, an electric circuit, and a switchwhereby the magnet may be made to form a part of said circuit to renderit active to attract the armature for the purpose of reciprocating rod36, to operate the feed-mechanism which moves the solder.

In testimony whereof we hereunto set our signatures in presence of twowitnesses.

WILLIAM H. OSBORNE. GEORGE R. MEITZLER. Witnesses:

(J. SPENGEL, O. FINN.

